A typical cotton harvester includes a series of different mechanisms which are driven by an engine. Although interrelated to effect a cotton harvesting operation, each mechanism is enabled at different ranges of engine speed to effect a specific function.
a conventional cotton harvester includes a series of harvesting units connected to a forward end of a frame. In a preferred form, each harvesting unit includes a harvesting mechanism for harvesting cotton from cotton plants as the harvester is moved over a field. The harvested cotton is conveyed through a duct system to a cotton receptacle. A fan mechanism provides a source of air which is sued to propel the cotton through the ducts and into the receptacle. Moreover, it is known to use a compactor mechanism within the receptacle for compressing the cotton and thereby increasing the capacity of the receptacle.
Many of today's harvesters include an operator presence system for controlling operation of the harvesting mechanism during normal harvesting operations. The operator presence system is provided to reduce exposure to the harvesting mechanism during harvester operation. A by-pass circuit incorporated into such a system, however, permits operation of the harvesting mechanism in a manner facilitating service and inspection thereof. As will be appreciated, the engine of the harvester, which ultimately is used to drive the harvesting mechanism, should be governed to limit engine speed during use of the by-pass circuit.
The fan mechanism develops an air flow within the harvester and includes a fan which is selectively connected to a continuous drive. In the illustrated embodiment, the continuous drive includes a belt loosely entrained about drive and driven pulleys. The drive pulley is rotated in response to engine operation. A fan interlock mechanism regulates the tension on the belt and thereby selectively controls fan operation.
As will be understood, there is both a need and desire to operate the fan mechanism within a predetermined range of engine speeds. Understandably, there is quite a shock to the harvester if the fan mechanism is initially engaged at a higher range of engine speeds. Therefore, it is desirable to engage the fan mechanism when the engine idles or within a predetermined range of speeds which is a predetermined percentage of normal engine idle speed. Because the drive pulley of the continuous drive is driven from the engine, disengagement of the fan mechanism at relatively high engine speed is likewise undesirable. Belt wear, breakage and other problems typically result from disengagement of the fan mechanism at high engine speeds.
The compactor mechanism of the harvester compresses cotton within the receptacle and thereby enhances capacity of the receptacle. The compactor mechanism typically operates at a high range of engine speeds when the cotton flow to the receptacle is maximized. It is desirable, therefore, to disable the compactor mechanism in a low range of engine speeds when it is not essential to harvester operation and to not draw needed energy and performance from other mechanisms on the cotton harvester.
Heretofore known cotton harvesters have a relatively complicated system for enabling and disabling different mechanisms on the harvester. One such system includes a myriad of microswitches and linkages which usually operate as a function of the engine throttle position. Operators of the cotton harvester have been known to successfully override or bypass the known systems by quickly engaging the microswitches. The ability to override the system, however, also typically results in wear and tear on the belts and/or other power transfer mechanisms used to operate the different mechanisms on the cotton harvester.
Because the harvesting season is relatively short, the operator does not want to spend valuable time replacing belts and repairing other devices to continue the harvesting operation. Another problem with linkages and microswitches involves their adjustability. As will be appreciated, each of the linkages and microswitches used to operate the different mechanisms need to be physically adjusted to achieve the desired operating range within which the different mechanisms operate. Moreover, the addition of microswitches and linkages to the harvester to control operation of the different mechanisms also increases the cost of the harvester and the complexity thereof.